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Explain why the amount of solar radiation absorbed by the earth's surface varies from place to place.

Land covered in concrete and buildings alters the albedo of a pace because dark colours will absorb, rather than reflect incoming sunlight. This creates 'urban heat islands' where temperatures are higher whe...
AS
Answered by Alice S. • Geography tutor
9641 Views

How should I structure an essay in an exam?

When writing an essay in an exam, try to ensure that your answer is focused, well structured and supported by evidence. To start with, it is a good idea to create a brief plan for your essay. This should inc...
CK
Answered by Charlotte K. • History tutor
3237 Views

How can I calculate the maximum value of the compound angle formulae Rsin(x+a) and Rcos(x+a)?

Often, the compound angle formulae can seem quite offputting, especially since exam pressures can mean the random "R" at the front of an angle addition formulae appears confusing. However, finding ...
LB
Answered by Luke B. • Maths tutor
16145 Views

Why is atrial repolarisation not present on an ECG yet ventricular repolarisation is?

This is because the QRS complex on the ECG (which represents the Ventricular depolarisation) is at such a high magnitude, it masks the electrical signals that occur due to atrial repolarisation as these two ...
SG
4267 Views

using the substitution u=6-x^2 integrate (x^3)/(6-x^2)^1/2 with respect to x, between 1 and 2

First we calculate du/dx = -2x and rearrange to get dx as the subject, dx=du/(-2x). Now we change the limits of integration because we are now integrating with respect to u. So the bottom limit will be u(1) ...
DB
Answered by Daniel B. • Maths tutor
5671 Views